In the United States, there are two common commercial alternating current electrical services--208 volts, three phase, and 480, three phase. In three phase electrical service there are typically four wires. Three so-called hot wires and one so-called neutral wire or grounded conductor. Typically, each hot wire is associated with one of the three phases. By identifying each wire with a particular phase, such as phase A, B, or C, the wiring may be installed in a manner to limit the induction that may occur as current flows through the wire. This is a well-known property of electricity transmission and is typically taken into account in designing commercial electrical services.
To aid the electrician in properly installing or servicing three-phase electrical installations, it has been a trade standard to use wiring that is color coded for each phase. For example, in the United States in the Chicago, Ill., metropolitan area, it has been at least a trade standard to color code wires as follows: in 208 volt three-phase service, a black wire for phase A, a red wire for phase B, a blue wire for phase C, and a white wire for neutral. As is well-known, electrical wiring typically comprises a solid or stranded copper core covered by an insulator of normally solid color. The colors identified above refer, of course, to the color of the insulator over the copper conductor. For 480 volt three-phase service, it has been at least a trade standard in the Chicago, Ill., metropolitan area to use brown, orange and yellow wires for phases A, B, and C, respectively, and grey for neutral.
In the typical electrical distribution equipment for three-phase alternating current, the phases are sequential. For example, in the power distribution panel, circuits 1 and 2 may be A phase, 3 and 4 may be B phase, 5 and 6 may be C phase, and so on, up to as many as 42 circuits. Thus, the colors associated with a particular circuit or phase are repeated sequentially.
When an electrician installs the wires associated with a particular circuit, the electrician must install a wire of the proper color and keep track of the circuit in which it is to be installed. Previously, the electrician would tag the wire with an adhesive marker bearing the particular circuit number. For example, if the electrician is required to install electrical wire for circuit 23 in a 208 volt, three-phase service, he must recognize that circuit 23 is associated with the C phase and the color code for the C phase is blue. To figure out that the proper color wire for circuit 23 is blue is both time consuming and subject to potential error by the electrician. This can be especially important when the installation requires many wires to be pulled through the conduit. If, for example, a blueprint requires the electrician to pull wires for many different circuits through the same conduit, the electrician needs to know quickly what color is associated with each particular circuit, and substantial time and money is wasted if an incorrect wire is pulled.
It is well-known in the electrical service installation area to attach numerical labels to each wire that is associated with a particular circuit and/or phase. These labels have typically been provided in sheets or small booklets of sheets containing a series of adhesive-backed strips bearing one of a series of numbers. For example the W. H. Brady Company of Milwaukee, Wis., supplies such wire markers under its part number PWM-PK-3. Similar wire markers are provided also by other manufactures such as Thomas & Betts of Memphis, Tenn., and the Panduit Company of Tinley Park, Ill. Typically these pull-off labels or strips use black numbers on a white background. However, numbers are also available in other color backgrounds, but typically the background color has no relationship to the color of the wire to be installed, and an entire series of numbers, such as 1-50, are provided on labels having the same color background. Suppliers have also supplied different color tags that are blank.
Accordingly, none of the known prior art wire markers have taken into account the difficulty that electricians face when having to pull a large number of wires associated with many circuits to assure that the proper color wire is associated and installed for the proper circuit or phase.
Accordingly, it is general object of the present invention to provide a wire marker, method and system that overcomes the drawbacks of the prior art and assists the electrician in determining and installing the proper wire for the proper circuit or phase.